Electronic module and method of manufacturing the same

ABSTRACT

An electronic module is provided, which comprises a first carrier; an electronic chip comprising at least one electronic component and arranged on the first carrier; a spacing element comprising a surface arranged on the electronic chip and being in thermal conductive connection with the at least one electronic component; a second carrier arranged on the spacing element; and a mold compound enclosing the electronic chip and the spacing element at least partially; wherein the spacing element comprises a material having a CTE value being matched with at least one other CTE.

The present application is a continuation of U.S. patent applicationSer. No. 14/214,962, filed Mar. 16, 2014, incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

The present invention relates to an electronic module. Moreover, thepresent invention relates to a method of manufacturing an electronicmodule.

DESCRIPTION OF THE RELATED ART

In the art a plurality of electronic modules are known which comprisesan electronic or semiconductor chip providing some electronicfunctionality. The electronic chip may be arranged or placed on acarrier or board and may be housed or packaged by a mold compoundenclosing the electronic chip.

In particular, due to the housing by the mold compound the dissipationof heat generated by the electronic chip may be an object. This isparticularly true in case the electronic module forms or is part of apower module, i.e. a module adapted and intended to handle a rather highpower, e.g. several orders of magnitudes higher than for electronicmodules used in the field of information technology.

Such power modules are used in electro motors, e.g. in the field ofelectric vehicles. These electro motors are typically heavily strainedor stressed in operation during the charging and discharging processesleading to a high and rapid heat generation which may be destructive forthe function of the batteries and motors. Thus, the dissipation of thegenerated heat is an important issue to be taken into consideration whenconstructing or designing such power modules. For example, materials maybe used for substrates of a chip mounting or when manufacturing leadframes, wherein the materials having a high thermal conductivity.Additionally, a heat conductive material can be used as a top layer orouter layer of the electronic module in order to provide a large contactarea or interface to the environment which may function as a heat sinkfor the module or package. In order to improve the heat dissipation heatsinks may be provided on both main surfaces of the power module. Theheat sinks are thermally coupled to the semiconductor chip wherein oneheat sink may be used for cooling one side of the chip while the otherheat sink is in thermal contact to the other side. The heat sinks inturn may be thermally coupled to the outside or environment by airconvection or liquid cooling.

A further problem which may arise from the relative high charging ordischarging currents is the mechanical stress induced due to temperaturechanges during an operation cycle. Depending on the environmentalconditions and the currents temperature changes from −40° to +150° C.may occur, leading to relative high thermomechanical stresses in theelectronic module.

While the described electric module may exhibit good quality of functionthere may still potential room to provide improved electronic modules.

SUMMARY OF THE INVENTION

Thus, there may be a need to provide electronic modules and a method ofmanufacturing the same wherein the electronic module provides for goodoperation for a long time, e.g. many temperature cycles, and enabling alow failure rate of the electronic module.

According to an exemplary aspect an electronic module is provided, whichcomprises a first carrier; an electronic chip comprising at least oneelectronic component and arranged on the first carrier; a spacingelement arranged on the electronic chip and being in thermal conductiveconnection with the at least one electronic component; a second carrierarranged on the spacing element; and a mold compound enclosing theelectronic chip and the spacing element at least partially; wherein thespacing element comprises a material having a coefficient of thermalexpansion value being matched with at least one coefficient of thermalexpansions selected out of the group of coefficients of thermalexpansion consisting of: a coefficient of thermal expansions of thefirst carrier; a coefficient of thermal expansions of the secondcarrier; a coefficient of thermal expansions of the electronic chip; anda coefficient of thermal expansions of the mold compound.

According to an exemplary aspect an electronic module is provided,wherein the electronic module comprises: a first conductive board; anelectronic chip comprising at least one electronic component andarranged on the first conductive board; a spacing element arranged onthe electronic chip and being in conductive connection with the at leastone electronic component; a cover layer arranged on the spacing element;and a mold compound enclosing the electronic chip and the spacingelement at least partially and having a coefficient of thermal expansionvalue of x ppm/K; wherein the spacing element comprises a materialhaving a coefficient of thermal expansion value laying in a rangebetween (x−4) ppm/K and (x+4) ppm/K.

According to an exemplary aspect a method of manufacturing an electronicmodule is provided, wherein the method comprises providing a firstcarrier; arranging an electronic chip comprising at least one electroniccomponent on the first carrier; contacting a spacing element to theelectronic chip; contacting a second carrier to the spacing element;molding a mold compound at least partially around the spacing elementand the electronic chip, wherein the spacing element comprises amaterial having a coefficient of thermal expansion value being matchedwith at least one coefficient of thermal expansions selected out of thegroup of coefficients of thermal expansion consisting of: a coefficientof thermal expansions of the first carrier; a coefficient of thermalexpansions of the second carrier; a coefficient of thermal expansions ofthe electronic chip; and a coefficient of thermal expansions of the moldcompound.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of exemplary embodiments of the invention and constitute apart of the specification, illustrate exemplary embodiments of theinvention.

In the drawings:

FIGS. 1A to 1C show cross sectional views of an electronic moduleaccording to an exemplary embodiment.

FIG. 2 shows results of simulations concerning creep strain stress.

FIG. 3 shows a schematic flowchart of a method of manufacturing anelectronic module according to an exemplary embodiment.

DESCRIPTION OF FURTHER EXEMPLARY EMBODIMENTS

In the following, further specific exemplary embodiments of theelectronic module and the method of manufacturing the same will beexplained. It should be noted that embodiments described in the contextof the electronic module may also be combined with embodiments of themethod of manufacturing the electronic module and vice versa.

In particular, accordingly a gist of an exemplary embodiment may be seenin providing an electronic module comprising an electronic chipsandwiched between a first conductive board and a spacing element and anadjoining second conductive board, wherein the electronic modulecomprising a mold compound at least partially enclosing the electronicchip and the spacing element, wherein an coefficient of thermalexpansion (CTE) of the spacing element is adapted to at least onecoefficient of thermal expansions selected out of the group ofcoefficients of thermal expansion consisting of: a CTE of the firstconductive board, a CTE of the second conductive board, a CTE of theelectronic chip and a CTE of the mold compound. In particular, the moldcompound may be applied by molding, e.g. by casting or injectionmolding.

It should be noted that of course one or more of the CTEs of thematerials of the electronic module may be matched to each other. Inparticular, the CTE of the spacer material may be matched with the CTEof the first conductive board and/or the CTE of the second conductiveboard and/or the CTE of the electronic chip and the CTE of the moldcompound. Preferably, the CTE of all these components are matched toeach other, e.g. the CTE values of all these components may be in apredetermined range, e.g. may only differ from each other in an intervalof ±6 ppm/K or even ±5 ppm/K. It should be noted that as well the CTE ofa solder paste may be taken into account when matching the CTEs witheach other. Preferably, the matching process may be performed in a wayto reduce the mechanical stress induced by temperature changes.

Additionally or alternatively the CTE of the spacing material may bematched to the sum or the mean value of all CTEs of the above describedlayers or components. For example, the sum or the mean value may becalculated as a weighted sum or mean value, e.g. taking into account thethickness of the different layers or components. Furthermore, it shouldbe mentioned that all CTEs may in particular be measured in atemperature range between 20° C. and 300° C., in particular 25° C. and150° C. For example, the CTEs may be determined by measuring anextension in one direction at a first temperature, e.g. 25° C. and thenmeasuring the extension in the one direction at a second temperature,e.g. 150° C. and determining then the CTE from the respective measuredvalues. Thus, the CTE may be a mean or average CTE. It should be notedthat preferably the different CTEs are measured under the samecircumstances and/or by the same determination method.

The term “matched” or “substantially matched” may particularly denotethe fact that a difference between the coefficients of thermal expansion(CTE) of the spacer or spacing elements material and of the otherelement (to which it is matched) may be less than a predeterminedthreshold value. The respective threshold value may be depending on thespecific application for which the electronic module is intended to beused in. For example, the threshold value may be 12 ppm/K, preferably 10ppm/K or even less, e.g. 8 ppm/K or even 6 ppm/K, all of the stated CTEsmay be measured or determined at a temperature of 25° C. or an intervalbetween 25° C. and 150° C. In particular, the CTEs of all describedcomponents or compounds, i.e. the mold compound, the spacing element,the first carrier, the second carrier, and the electronic chip may layin a range of about 3 ppm/K and 15 ppm/K, i.e. in a range of about ±6ppm/K of a mean value of 9 ppm/K. That is, the value of CTE of thematerial of the spacing element may be in the range of 9 ppm/K±6 ppm/K,more particularly in the range of 11 ppm/K±3 ppm/K. It should be notedthat the term “matched” also includes that the respective material is aresult of a deliberately or arbitrarily selection taking into accountthe CTE of the spacing element material and of the other othersmaterials or elements of the electronic module. It should bedistinguished from an accidentally matching resulting by chance. Itshould be mentioned that when selecting the spacing element material aswell the wettability and/or coatability of the spacing material may betaken into account. That is, the spacing material may be a materialwhich can be wetted or coated in a sufficient extent that a solderingstep may be performed.

For example, for a typical value of about 10 ppm/K of the CTE for atypical mold compound the CTE value for the spacing element may rangebetween 5 ppm/K and 15 ppm/K which is lower than the CTE of copper whichis often used in that field of electronic modules for spacing elements.

In other words the coefficient of thermal expansion of the material ofthe spacing element (spacing element material) may be adapted to or atleast partially matched with the coefficient of thermal expansion of themold compound or any other compound of the electronic module. Inparticular, the electronic chip may be soldered to the carrier, e.g. acopper board, aluminium board or direct copper bonding (DCB) board ordirect aluminium bonding (DAB) board. In addition or alternatively thespacing element or spacer may be soldered to the electronic chip.Preferably, the material of the spacing element or spacer may be amaterial which is solderable, i.e. the material may be wettable.

In addition or alternatively the coefficient of thermal expansion of thespacing element material may be matched with the coefficient of thermalexpansion of the carriers and/or of the chip.

The term “conductive” may particularly denote the fact that a material,element or structure may be electrically and/or thermally conductive,e.g. may mean that the electrical conductivity or thermally conductivityis above a given threshold, which will be defined by a person skilled inthe art according to the given conditions.

In particular, a conductive material may have a high electricalconductivity, e.g. an electrical conductivity being above apredetermined threshold. The predetermined threshold may be inparticular 1*10⁶ S/m, preferably 10*10⁶ S/m, more preferably 15*10⁶ S/m,and even more preferably 20*10⁶ S/m.

In particular, the spacing element comprises a conductive material. Forexample, the conductive material may be thermally and/or electricallyconductive. The spacing element may also fulfil a levelling effectbalancing differences in height of components or layers of theelectronic module. In particular, the electronic chip may comprise ormay be formed by a power transistor, i.e. a switching element suitablefor switching electrical power in the amount of several tens or hundredsof watts. Such power transistors have to be distinguished fromtransistors used for switching information signals, e.g. in integratedcircuits of a processor or memory. Alternatively, the electronic modulemay comprise a dense array of electronic circuits. It should be notedthat the spacing element or spacer may be used for providing anelectrical path from the electronic chip to another component of theelectronic module and/or to the exterior of the electronic module. Thatis, the spacer may be part of the electrical circuit or circuitry formedby or in the electronic module.

By providing an electronic module comprising a spacer or spacing elementcomprising a material having a CTE matched to at least on othercomponent of the electronic module, it may be possible that delaminationof the mold compound and/or between the electronic chip and the spacingelement and/or the mold compound is reduced. Such a delamination mayparticularly occur due to different thermal expansion (during operation)of the mold compound and of the electronic chip and/or the material ofthe spacing element and may lead to the failure of the electronicmodule, e.g. due to breaking of electrical paths from and to theelectronic component. In particular, an improved electronic module maybe provided which may fulfil its functions for more temperature cycles,i.e. heating up and cooling down again, without breaking of electronicsor electric paths in the electronic module due to delamination effects,for example.

In particular, the electronic module may be a power module, e.g. a powertransistor or a similar electronic module adapted to withstand highvoltage. The term “high voltage” may particular denote a voltage whichis higher than typical voltages used for information signals. Forexample the power transistor may withstand a voltage of hundred or evenseveral hundreds of volts. In particular, the electronic chip may beelectrically connected to the carrier or conductive board, e.g. by wirebonding, soldering or surface mounting technology.

It should be noted that the electronic module may comprise additionalspacing elements which may be arranged laterally with respect to eachother and/or may be arranged vertically with respect to each other, i.e.may form a stacked arrangement. Additional, several electronic chips maybe arranged horizontally and/or vertically with respect to each other inor at the electronic module. The mold compound may comprise athermoplast material, a thermoset material, a plastomere material or anepoxy material.

According to an exemplary embodiment of the electronic module thematching is performed in such a way that a mechanical stress in theelectronic module due to temperature changes is minimized.

In particular, several or all of the cited component may comprise or mayconsist of a material having a CTE which is selected in such a way thatthe overall mechanical stress due to temperature changes, e.g. during atypical thermocycle, is minimized or at least below a predeterminedthreshold. A sufficient threshold may be defined by a number ofthermocycles which the electronic module has to withstand withoutdelamination of components or breakages of electrical paths orconnections. Thus, thresholds may be defined in specific test standards,e.g. in automotive standards, defining a minimal robustness. Forexample, the respective electronic module may fulfil the AEC-Q100 or theAEC-Q101 standard. It should be mentioned that the matching of the CTEsof specific components may be more important with respect to theresulting mechanical stress than for other components. For example,while solder paste used for soldering processes may still have arelatively high CTE value compared to other components the influence ofits CTE may be less important than the influence of other componentslike the spacing element, the carriers or the mold compound. However,when selecting or matching the CTEs the one of the solder paste may aswell be considered or taken into account.

According to an exemplary embodiment of the electronic module thematching is performed in such a way that values of coefficient ofthermal expansion of the spacing element material and of the matchedcoefficient of thermal expansion is within a range of ±6 ppm/K.

According to an exemplary embodiment of the electronic module thecoefficient of thermal expansion of the spacing element material is inthe range of 6 ppm/K and 16 ppm/K. In particular, the CTE may be in therange of 7 ppm/K and 15 ppm/K or even in the range of 8 ppm/K and 14ppm/K. It should be noted that the According to an exemplary embodimentof the electronic module the spacing element material has an electricalconductivity above a predetermined threshold.

In particular, the predetermined threshold may be 1*10⁶ S/m and moreparticular 2*10⁶ S/m and even more particular 3.5*10⁶ S/m.

According to an exemplary embodiment of the electronic module thespacing element material has a thermal conductivity above apredetermined threshold.

In particular, the predetermined threshold may be 50 W/mK at 25° C.,preferably 100 W/mK at 25° C., more preferably 150 W/mK at 25° C.

According to an exemplary embodiment of the electronic module thespacing element material is a matrix compound. In particular, the matrixcompound may be a metal matrix compound.

The term “matrix compound” or “matrix based material” may particularlydenote a material comprising a matrix formed by a base material of thematrix compound in which a further material, the so called reinforcementmaterial, may be included, e.g. by diffusion. In particular, the basematerial or matrix material may be aluminium or copper, for example.

According to an exemplary embodiment of the electronic module the matrixcompound comprises a metallic matrix material. In particular, the matrixmaterial may be a wettable and/or coatable material in order to increasethe suitability for soldering.

According to an exemplary embodiment of the electronic module areinforcement material of the matrix compound, is selected out of thegroup consisting of: silicon carbide (SiC); tungsten (W); and molybdenum(Mo).

According to an exemplary embodiment of the electronic module the spacerelement material is selected out of the group consisting of: AlSiC; CuW;and CuMo.

In particular, the AlSiC material may be so called AlSiC-9, a materialcomprising 37 vol % of aluminium alloy (e.g. a so called 356.2 aluminiumalloy) and 63 vol % of SiC; AlSiC-10, a material comprising 45 vol % ofaluminium alloy and 55 vol % of SiC, or AlSiC-12, a material comprising63 vol % of aluminium alloy and 37 vol % of SiC. It should be mentionedas well that the spacer element material may be selected as well withrespect to its wettability and/or coatability. In particular, it shouldbe wettable and/or coatable to a sufficient extend that solderingprocesses can be performed.

According to an exemplary embodiment of the spacer element material isselected out of the group consisting of AlSiC comprising a SiC contentbetween 25% and 80% by volume, in particular between 30% and 60%; CuWcomprising a W content between 20% and 85% by volume; and CuMocomprising a Mo content between 30% and 90% by volume.

According to an exemplary embodiment of the electronic module the firstconductive board and or the first carrier comprises a material selectedout of the group consisting of: copper and aluminium.

According to an exemplary embodiment of the electronic module the secondconductive board or the second carrier comprises a material selected outof the group consisting of: copper and aluminium.

In particular, it may be that the first conductive board and the secondconductive board comprises or may consist of the same material, e.g.both may comprise or may consist of copper. It should be mentioned thatone or more boards or carriers may be coated as well, e.g. by a NiPcoating, for example.

According to an exemplary embodiment of the electronic module thecoefficient of thermal expansion of the spacer material is lower than 16ppm/K.

In particular, the CTE of the spacer material may be lower than 15 ppm/Kmore preferably the CTE of the spacer material may be in the rangebetween 6 and 16 ppm/K, e.g. in the range between 8 and 14 ppm/K. Thevalues of the CTE given throughout the whole application may bedetermined as an average value of the CTE determined based onmeasurements at 20° C. and 300° C.

According to an exemplary embodiment of the electronic module the spacermaterial coefficient of thermal expansion value is substantially matchedwith a coefficient of thermal expansion value of the mold compound.

According to an exemplary embodiment of the method the contacting of thespacing element comprises a soldering step.

In particular the spacing element or spacer may be soldered to theelectronic chip. The soldering step may comprise the provision of asoldering material and or of a fluxing agent on the electronic chipand/or on the spacing element.

According to an exemplary embodiment of the method the contacting of thesecond carrier comprises a soldering step.

That is, according to an exemplary embodiment of the electronic modulethe spacing element is fixed to the electronic chip and/or to the secondcarrier or second conductive board by a solder structure. In particular,for all soldering steps a soldering material and/or soldering agent maybe applied. It should be noted that the soldering step used incontacting the spacing element and the soldering step used in contactingthe second carrier may be one single soldering step. For example, asolder paste may be arranged on the electronic chip and/or the spacingelement before the spacing element is arranged on the electronic chip. Asolder paste may be arranged on the spacing element and/or the secondcarrier before the second carrier is arranged on the spacing element.Then a single soldering step is used.

In particular, the solder structure may be a solder layer. The solderstructure, formed for example by solder balls, solder paste, solderbumps or the like, may provide for an efficient way to electrically andthermally connecting the spacing element and the electronic chip to eachother and at the same time providing a sufficiently strong connectionbetween the same.

According to an exemplary embodiment the method further comprisesselecting the spacing element material taking into account thecoefficient of thermal expansion of the spacing element material.

In particular, the CTE of the spacing material may be arbitrarilyconsidered or taken into account when choosing or selecting the spacingmaterial by comparing and matching the same with CTEs of other materialsor components of the electronic module. The selecting may take intoaccount the object or goal to reduce thermomechanical stresses duringthermocycles of the use of the electronic module.

According to an exemplary embodiment of the method the selecting furthertakes into account a coefficient of thermal expansion of the acoefficient of thermal expansions of the first carrier; the coefficientof thermal expansions of the second carrier; the coefficient of thermalexpansions of the electronic chip; and the coefficient of thermalexpansions of the mold compound.

DETAILED DESCRIPTION OF THE FIGURES

The above and other objects, features and advantages of the presentinvention will become apparent from the following description and theappended claims, taken in conjunction with the accompanying drawings, inwhich like parts or elements are denoted by like reference numbers.

The illustration in the drawing is schematically and not necessarily toscale.

FIG. 1A to 1C show cross sectional views of an electronic module, e.g. adouble sided cooled module (DSC-module), according to an exemplaryembodiment. In particular, FIG. 1A shows an electronic module 100comprising a first carrier or first conductive board, e.g. a directcopper bonding (DCB) board, 101 on which electronic chips 102 arearranged. The electronic chips 102 may be fixed to the first carrier bysoldering which is indicated in FIG. 1A by a thin layers 103.Furthermore, spacing elements or spacers 104 are arranged or contactedto the electronic chips, which can be as well soldered to the electronicchips indicated by layers 105. As a second outer layer a second carrieror second conductive board 106 is contacted to the spacing element aswell by a solder layer 107. Thus, the spacing element or spacer and thesecond outer layer may be soldered to each other as well. It should bementioned that the soldering step used for soldering the spacing elementto the electronic chip and the soldering step used for soldering thesecond outer layer onto the spacing element may be two distinctsoldering steps or processes or may be performed by a single solderingstep or process. This holds true for all of the embodiments describedherein. For encapsulating the electronic or electric components at leastpartially a mold compound 108 is molded, e.g. by a transfer moldprocess, around the electronic or electric components. In particular,the mold compound may encapsulate the electronic chips, the spacingelements and parts of the first and second carriers, while an outersurface of the first and second carriers may still be exposed so thatheat generated by the electronic components, in particular, theelectronic chips can be dissipated. In addition the exposed surfaces maybe used to discharge or convey heat generated by the electronic chipsout of the electronic module.

FIG. 1B and FIG. 1C schematically illustrates mechanical stress orstrain which may be induced during a thermocycle of the electronicmodule. The arrows 110 in FIG. 1B indicate the thermal expansion in avertical direction in FIG. 1B, i.e. the direction perpendicular to thelayered structure of the electronic module 100. FIG. 1B shows tensilestress which acts on the mold compound and may cause delamination of themold compound from the conductive board. The arrows 120 in FIG. 1Cindicate the thermal expansion in a horizontal direction in FIG. 1C,i.e. the direction parallel to the layered structure of the electronicmodule 100. FIG. 1C shows lateral stress on solder joints and moldcompound.

The mechanical stress may in particular induced due to the fact that thedifferent materials of the different components described in connectionwith FIG. 1A have different coefficient of thermal expansions (CTE). Forexample, a typical value of a DCB board is about 8 ppm/K, for anelectronic chip in the range of 4 ppm/K, for a copper spacer (which is atypical spacer material in the prior art) about 18 ppm/K while a typicalmold may have a CTE of about 10 ppm/K. Thus during a thermocycle whichcan include temperatures between −40° C. and +150° C., mechanical stresswill arise which may lead to a delamination and possible breaking ofelectrical paths to and from the electronic chip.

In order to reduce the thermal stress in particular, the material of thespacing element is matched more closely with the other components of theelectronic module with respect to their CTEs. For example, CuW or AlSiCmaterial having an SiC percentage or fraction between 25% and 80% byvolume (e.g. the so called AlSiC-9, AlSi-10 or AlSiC-12 materials) maybe used which have CTEs between 8 and 12 which is closer to the otherCTEs. Thus, when using one of the cited materials for the spacingelement, thermal stress may be reduced.

FIG. 2 shows results of simulations concerning creep strain stress. FIG.2 shows graphs indicating the simulation results of creep strain stressper cycle in [m/m] vs. CTE of the spacing material in 10⁻⁶ ppm/K. Inparticular, maximal and minimal stresses are indicated in FIG. 2 by thedotted line 200 and continuous line 201, respectively. As can be seen anearly constant (low) plateau of maximal stress is present in the rangeof CTEs between about 7 ppm/K and 14 ppm/K. For reference, some verticallines are depicted in FIG. 2 as well which indicate the CTE forAlSiC-9/CuW (202), AlSiC-10 (203), AlSiC-12 (204) all of which are lyingwithin the nearly constant plateau. For comparison Cu having a CTE ofabout 18 ppm/K is as well indicated in FIG. 2 by line 205. As can beseen in FIG. 2 the creep strain stress may be reduced by a factor ofmore than 2 by using a material for the spacing elements having amatched CTE instead of Cu or a copper alloy. For some furtherinformation, some specific values of the materials Cu, CuW, AlSiC-9,AlSiC-10, and AlSiC-12 are given in FIG. 2 as well. With respect to theCTE values of the AlSiC compounds it should be mentioned that these maybe determined based on a first measurement at 25° C. and a secondmeasurement at 150° C. to determine an average CTE. It should bementioned that further characteristics of the AlSiC compounds may befound in “Aluminum Silicon Carbide (AlSiC) Microprocessor Lids and HeatSinks for Integrated Thermal Management Solutions” of M. A. Occhioneroet al., IMAPS Denver 2000.

FIG. 3 shows a schematic flowchart of a method of manufacturing anelectronic module according to an exemplary embodiment. In particular,the method 300 comprises providing a first carrier (step 301) which maybe for example a DCB or DAB board. Afterwards an electronic chipcomprising at least one electronic component is arranged on the firstcarrier (step 302), e.g. by soldering. Then a spacing element iscontacted to the electronic chip (step 303), e.g. as well by soldering.Subsequently a second carrier is contacted to the spacing element (step304), which again may be performed by a soldering step. Afterwards amolding compound is molded, casted or injected at least partially aroundthe spacing element and the electronic chip (step 305), formingbasically the electronic module. It should be noted that the CTE of thespacing element may be selected in a specific selection step in order tomatch the CTE to the CTEs of other components, e.g. the mold component,so that thermal stress may be reduced during use of the electronicmodule.

It should be noted that the term “comprising” does not exclude otherelements or features and the “a” or “an” does not exclude a plurality.Also elements described in association with different embodiments may becombined. It should also be noted that reference signs shall not beconstrued as limiting the scope of the claims. Moreover, the scope ofthe present application is not intended to be limited to the particularembodiments of the process, machine, manufacture, composition of matter,means, methods and steps described in the specification. Accordingly,the appended claims are intended to include within their scope suchprocesses, machines, manufacture, compositions of matter, means,methods, or steps.

What is claimed is:
 1. An electronic module comprising: a first carrier;an electronic chip comprising at least one electronic component andarranged on the first carrier, a spacing element arranged on theelectronic chip and being in thermal conductive connection with the atleast one electronic component; a second carrier arranged on the spacingelement; and a mold compound enclosing the electronic chip and thespacing element at least partially; wherein the spacing elementcomprises a material having a coefficient of thermal expansion valuebeing matched with at least one coefficient of thermal expansionsselected out of the group of coefficients of thermal expansionconsisting of: a coefficient of thermal expansions of the first carrier;a coefficient of thermal expansions of the second carrier; and acoefficient of thermal expansions of the mold compound.
 2. Theelectronic module according to claim 1, wherein the matching isperformed in such a way that mechanical stress in the electronic moduledue to temperature changes is minimized.
 3. The electronic moduleaccording to claim 1, wherein the matching is performed in such a waythat values of coefficients of thermal expansion of the spacing elementmaterial and of the matched coefficient of thermal expansion is within arange of ±6 ppm/K.
 4. The electronic module according to claim 1,wherein the coefficient of thermal expansion of the spacing elementmaterial is in the range of 6 ppm/K and 16 ppm/K.
 5. The electronicmodule according to claim 1, wherein the spacing element material has anelectrical conductivity above a predetermined threshold.
 6. Theelectronic module according to claim 1, wherein the spacing elementmaterial is a matrix compound.
 7. The electronic module according toclaim 6, wherein the matrix compound comprises a metallic matrixmaterial.
 8. The electronic module according to claim 6, wherein areinforcement material of the matrix compound, is selected out of thegroup consisting of: SiC; W; and Mo.
 9. The electronic module accordingto claim 1, wherein the spacer element material is selected out of thegroup consisting of: AlSiC; CuW; and CuMo.
 10. The electronic moduleaccording to claim 9, wherein the spacer element material is selectedout of the group consisting of: AlSiC comprising a SiC content between25% and 80% by volume; CuW comprising a W content between 20% and 85% byvolume; and CuMo comprising a Mo content between 30% and 90% by volume.11. A method of manufacturing an electronic module, the methodcomprising: providing a first carrier; arranging an electronic chipcomprising at least one electronic component on the carrier; contactinga spacing element to the electronic chip; contacting a second carrier tothe spacing element; molding a molding compound at least partiallyaround the spacing element and the electronic chip, wherein the spacingelement comprises a material having a coefficient of thermal expansionvalue being matched with at least one coefficient of thermal expansionsselected out of the group of coefficients of thermal expansionconsisting of: a coefficient of thermal expansions of the first carrier;a coefficient of thermal expansions of the second carrier; and acoefficient of thermal expansions of the mold compound.
 12. The methodaccording to claim 11, wherein the contacting of the spacing elementcomprising a soldering step.
 13. The method according to claim 11,wherein the contacting of the second carrier comprising a solderingstep.
 14. The method according to claim 11, further comprising:selecting the spacing element material taking into account thecoefficient of thermal expansion of the spacing element material. 15.The method according to claim 14, wherein the selecting further takesinto account a coefficient of thermal expansion of the a coefficient ofthermal expansions of the first carrier; the coefficient of thermalexpansions of the second carrier; the coefficient of thermal expansionsof the electronic chip; and the coefficient of thermal expansions of themold compound.